Open In Colab

LlamaIndex + DeepEval Integration

This code tutorial shows how you can easily integrate LlamaIndex with DeepEval. DeepEval makes it easy to unit-test your LLMs.

You can read more about the DeepEval framework here:

Feel free to check out our repository here:


Set-up and Installation

We recommend setting up and installing via pip!

!pip install -q -q llama-index
!pip install -U -q deepeval

This step is optional and only if you want a server-hosted dashboard! (Psst I think you should!)

!deepeval login

Testing for factual consistency

from llama_index.response.schema import Response
from typing import List
from llama_index.schema import Document
from deepeval.metrics.factual_consistency import FactualConsistencyMetric

Setting Up The Evaluator

Setting up the evaluator.

from llama_index import (
from llama_index.llms import OpenAI
from llama_index.evaluation import FaithfulnessEvaluator
import os
import openai

api_key = "sk-XXX"
openai.api_key = api_key
gpt4 = OpenAI(temperature=0, model="gpt-4", api_key=api_key)
service_context_gpt4 = ServiceContext.from_defaults(llm=gpt4)
evaluator_gpt4 = FaithfulnessEvaluator(service_context=service_context_gpt4)

Getting a LlamaHub Loader

from llama_index import download_loader

WikipediaReader = download_loader("WikipediaReader")

loader = WikipediaReader()
documents = loader.load_data(pages=["Tokyo"])
tree_index = TreeIndex.from_documents(documents=documents)
vector_index = VectorStoreIndex.from_documents(
    documents, service_context=service_context_gpt4

We then build an evaluator based on the BaseEvaluator class that requires an evaluate method.

In this example, we show you how to write a factual consistency check.

from typing import Any, Optional, Sequence
from llama_index.evaluation.base import BaseEvaluator, EvaluationResult

class FactualConsistencyEvaluator(BaseEvaluator):
    def evaluate(
        query: Optional[str] = None,
        contexts: Optional[Sequence[str]] = None,
        response: Optional[str] = None,
        **kwargs: Any,
    ) -> EvaluationResult:
        """Evaluate factual consistency metrics"""
        if response is None or contexts is None:
            raise ValueError('Please provide "response" and "contexts".')
        metric = FactualConsistencyMetric()
        context = " ".join([d for d in contexts])
        score = metric.measure(output=response, context=context)
        return EvaluationResult(

evaluator = FactualConsistencyEvaluator()
query_engine = tree_index.as_query_engine()
response = query_engine.query("How did Tokyo get its name?")
eval_result = evaluator.evaluate_response(response=response)
/usr/local/lib/python3.10/dist-packages/transformers/ UserWarning: The sentencepiece tokenizer that you are converting to a fast tokenizer uses the byte fallback option which is not implemented in the fast tokenizers. In practice this means that the fast version of the tokenizer can produce unknown tokens whereas the sentencepiece version would have converted these unknown tokens into a sequence of byte tokens matching the original piece of text.
{'success': True, 'score': 0.97732705}
/usr/local/lib/python3.10/dist-packages/deepeval/metrics/ UserWarning: API key is not set. Please set it by visiting

Other Metrics

We recommend using other metrics to help give more confidence to various prompt iterations, LLM outputs etc. We think ML-assisted approaches are required to give performance for these models.

  • Overall Score:

  • Answer Relevancy:

  • Bias: